The present invention relates to a receiver for amplitude modulated signals, more particularly to a receiver for measuring the amplitude of such signals.
A wide bandwidth amplitude measuring receiver is known which is used to provide a measurement in digital form of a receiver signal in the microwave range of frequencies. This known receiver includes an analog logarithmic amplifier whose output is supplied to an analog-to-digital converter. In practice, it is difficult to make a satisfactory analog logarithmic amplifier because a wideband diode has to be used and this can cause stability problems. Additionally such a diode has difficulty in maintaining its square-law characteristic over the full dynamic range which may be as high as 80 dB. Further disadvantages of this known receiver are that it is bulky, expensive and difficult to apply temperature control.